Muffle-furnace



W. 0. AMSLER.

MUFFLE FURNACE.

APPLiCATlON FILED mm. 1916.

1,341,031 Patented May 25, 1920.

2 suzns-suan I.

FIB.1.

Patented May 25, 192 0 2 SHEETS-SHEET 2.

W. O. AMSLER.

MUFFLE FURNACE.

FIT-3.2.

APPLICATION FILED APR-3| 1916.

WALTER O. AMSLER, OF EDGEWOOD, PENNSYLVANIA.

MUFFLE-FURNACE.

Specification of Letters Patent.

Patented May 25, 1920.

Application filed April 3, 1916. Serial No. 88,462.

I0 all whom it may concern Be it known that I, WVALTER O. AMsLER, a citizen of the United States, residing at Edgewood, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Muffle-Furnaces, of which the following is a specification.

My invention relates to mufl'le furnaces generally, also to the construction of a mufhe furnace adapted to form part of a leer especially intended for use in connection with annealing glass articles, and further to a furnace for enameling purposes.

The objects of the invention are to provide means whereby a uniform temperature throughout the mufl'le furnace chamber may be maintained; to obtain economy of fuel; to provide effective means for preheating the air adapted to mix with the fuel in the combustion space; and to provide means for preheating the ware-conveying means preliminarily to the deposit of the articles to be annealed or enameled thereon, and to generally improve the construction of an apparatus of this character.

In the accompanying drawings whlch illustrate an application of my invention,

Figure 1 is a vertical sectional view.

Fig. 2 is a vertical section at right angles to Fig. 1.

Fig. 3 is a horizontal section on the line 33 of Fig. 2.

Referring to the drawing, 1 is an admission pipe extending longitudinally of the furnace from front to rear of the same and centrally thereof, and adapted for the supply of gaseous fuel, preferably producer gas, and this pipe communicates by a longitudinal series of short downwardly conducting branch pipes 2 with a series of lateral air passageways t formed at the upper part of the furnace construction between the walls 5 and 6. Auxiliary pipes 7 lead into the branch pipes 2 below the producer gas pipe for the purpose of admitting either natural gas or oil as the fuel medium to the branch pipes and from thence to the passageways 4:, for the purpose of enabling either of said other fuels to be used in lieu of the producer gas, when desired. The passageways 4 divide from the central intake pipes and lead laterally therefrom, and each lateral branch of such passageway communicates at its end with a vertical flue 8, these constituting the air conduits down the sides of the furnace construction. The air from these conduits mixes with the fuel supply from the corresponding intake pipes 2 at the respective terminations of these pipes to provide combustible mixtures. For the purpose of providing initial combustion, the walls 6 are provided with openings 9 through which a lighting tool may be inserted, after which combustion is maingained by the flame in the combustion chamers.

The air passages are adapted to be supplied with air from two series of air inlets 11, one at each side of the furnace wall construction. The air, after entering the inlets of one of these series passes into one of a pair of recuperator constructions provided on each side of the furnace and having tortuous passageways formed by horizontal walls 12, 13 and i l. In these recuperators, the air is adapted to be heated and to then pass upward through the side branches of the air passageways, and thence to the lower terminations of the fuel admitting pipes 2, where it mixes with the fuel.

The combustible mixture then passes into a series of lateral combustion chambers 15 extending over the muffle 16 which provides the furnace chamber 17 These combustion chambers communicate, at their ends, with vertical side flues 18, which communicate with the lateral spaces 19 below the muffle, thus establishing heating spaces entirely surrounding the muffle. The two passageways 19 running from each side of the muffle communicate at their inner ends with a central vertical flue 20 formed by and between the opposite end walls 21 of the recuperators. These flues 20 communicate with horizontal passageways 22 formed by and between the lower horizontal walls of the recuperators and a wall 23; the latter may and as illustrated does constitute the upper horizontal wall of a conveyer chamber 24, and from such passageways 22 the products of combustion are led by vertical side flues 25 to the horizontal passageways 26 which respectively communicate with exit flues 27 leading to a chimney flue 28 by which communication with the atmosphere is estabcuperator a lished. A longitudinal series of fines 27 is disposed in each side of the chimney flue, and these series are spaced part laterally and disposed on each side of the central line of the muflle, so that each series of lines will exert a separate draft on the products of combustion passing around the opposing sides of the mulile, whereby the heating gases are divided into separate streams which will effectively maintain a constant uniform temperature of the muffle.

It is evident that the structure thus far described relates to amuliie furnace broadly and to the manner of heating the same, and it is my intention to claim this matter broadly although the particular embod1- ment of my invention is shown in connection with a leer and a carrier for conveying articles to said leer.

[it ;the front end of the furnace, the redjacent to such end has the flue 2t) nearestto such front end blocked off by the horizontal wall 29 (see Fig. 2), and such wall and the front part of the recupe 'ator cons-tr ction project forwardly to provide chambers ill and 31 through which the heated gasesare led in a tortuous path, the object of such arrangement being to project a portion of the recuperator out .vardly ad acent to the vertical stretch of the conveyor 33, so that the ware carrying pans of the conveyer will be heated more effectively prior to the deposit of the articles thereon.

The endless conveyer 33 serves as the means for introdiution, automatically and continuously, of the articles to be treated into the nuule furnace, l

and from sucn furnace.outwardly to the coolin leer or tunnel ill. To thisend, such com I is provided with a series of pans on which the articles to .be annulled or enameled are placed, and the conveyer is adapted to run on a lower set of tracks 36 extending above the floor 8'7 of the leer and below the recuperators. The conveyer then passes over sprocket wheels 38. The conveyer from the upper sprocket passes into the mullie furnace along trac {S 39. :it the front end of the furi'iace, a hinge door 40 is provided which is adapted to be opened to permit the ware to be annealed or enameled to be placed upon the pans just hey are about to enter the furnace chamber. The ware, after passing through the furnace chamber where it is subjected to the proper temperature for annealing or enameling, is carried by the upper stretch of the conveyor out into the cooling leer tunnel 3 t, and the articles are removed from the conveyor the latter emerges from the tunnel. If the leer is not employed in onnection ith the muffle, ware may i removed at any convenient point after it passes through the furnaw.

The above construction provides an annealing or enameling furnace of the muffle type in which the combustible fuel mixture is directed downwardly from the upper part of the furnace construction around-all parts of the muffle, such downward flow of the gases being induced by the location of the intake above the mufile and of the exit fines below the furnace and at the lowest point of the construction which is, of course, the coolest part. Since the gases will flow toward the coolest points in seeking the path of least resistance, which coolest points are at the fines leading to the chimney, the heated gases will be caused to travel down- .Vtll't ly in their natural direction of flow and will be directed automatically by the differences in temperature toward the coolest part of the muffle, whereby a uniform temperature around all parts of the mufile will be maintained. A saving of fuel isalso obtained by providing this naturaldirection of flow. Owing to the fact that two-separate series ofexitflues spacedapart laterally of the mufile are provided and that the admission ports are located centrally of the muffle, the gases will be equallyidivided and directed to both sides of the n1uflle,and also should the temperature on one side of the mullle fall, greater drafton the gases will be induced toward such pointiand thus automatically restore the proper and uniform temperature.

Another important advantage in the above construction lies in the location of the recuperators between the two stretches of the conveyer, whereby the carrier pansare heated before they arrive atthepoint where the articles are to be deposited thereon.

rruother feature ofimportance is the construction prov. ling for the preheating of the air which mingles with the fuel to .produce the combustible mixture and the location of the air heating passageways between the combustion space and the outer wall of the furnace, whereby the radiation of .the heat from the combustion sgace isconserved and utilized for the heating of theair, and also loss of radiation of the combustion heat, irough an exposed outer muffle wall such as is customarily employed, avoided.

Owing to the separationeofthe combustion heating spaces intochambersdisposed in a series extending longitudinallyeof the muffle, heat-localizing individual heating units for the muffle are provided, bymeans of which arrangement longitudinal disperi sion of the gases and products of combustion is p ented and separate sections of the muflle individually and effectively heatedby direct contact of theseparate downwardly moving streams of gases against such limited sections only.

vl hat I claim is V 1. In a muflle furnace construction, in combination with a singleopen.endedmuflle having a plurality .of laterally extending independent combustion chambers adjacent the top of the same, and formed with centrally disposed fluid inlet passages, means leading from each of the combustion chambers to an exit at a point below the muffle,

means for admitting a gaseous combustible supply to said combustion chambers through said inlets above the muffle, and means for preheating air and mixing it with the gaseous supply above the muffle, said latter means including a recuperator structure disposed below the muffle.

2. In a muffle furnace construction, in combination with a single open ended muffle having a plurality of laterally extending independent combustion chambers adjacent the top of the same, said chambers each having a fluid inlet passage, means leading from each end of each combustion chamber to an exit at a point below the muffle, and centrally disposed means for admitting a gaseous combustible supply to said combustion chambers through said fluid inlet passages above the muflle.

3. In a muflie furnace construction, in combination with a muffle, means providing a plurality of combustion chambers adjacent to and above said muffle and extending laterally thereof, said chambers having centrally disposed fluid inlet passages, flues ad-' jacent the sides and bottom of the muffle and communicating with said chambers and providing with the same a continuous heating space extending around the muffle, means providing an air chamber adjacent to and entirely surrounding the heating space, means for admitting a gaseous fuel supply to the said combustion chambers through said inlets, means of communication between the air chamber and the combustion cha1nber adjacent said means of admission, means communicating with the heating space and leading to an atmosphere-communicating exit below the muffle, and recuperating means heated by the products of combustion located between the muffle and said exit.

l. In a muffle leer, in combination with a muffle, a plurality of independent combustion chambers disposed above the mu'ffle, means above the chambers for admitting fuel thereto, a flexible conveyer for the ar ticles to be treated adapted to travel through said muffle, said conveyer having the horizontal stretches thereof spaced apart for a portion of their lengths, recuperator means mounted between the said spaced stretches of the conveyer and having laterally prolonged means including chambers extending adjacent to the vertical stretch of the conveyer joining said horizontal stretches.

5. In a muffle leer, in combination with a muflle, means providing a combustion and heating space around said muffle, including a plurality of independent combustion chambers outside of and above the muffle, means for admitting a combustible gaseous supplylocated above said mufile and communicating with said chambers, said chambers each having a centrally disposed fluid inlet, exit means for the products of combustion located below the muflie and'conr municating with the ends of the combus tion chamber, a flexible endless conveyer having means for carrying the articles to be treated and having portions of the horizontal stretches thereof spaced apart vertically, recuperator means mounted between the heating space and the lower horizontal stretch of said conveyer, and a preheating air conduit leading from said recuperator means around the heating space and communicating with said space adjacent the point of admission of the gaseous supply.

6. In a muffle leer, a single muffle, a series of fuel admitting members, a series of independent combustion chambers having centrally disposed fluid inlet passages corresponding respectively to said members, a series of vertical and horizontal flues adjacent the sides and bottom of the muffle and correspondingly communicating with said combustion chambers whereby heating spaces extending entirely around the muflle are provided, exit flues below the said bottom flues, and a series of air flues adjacent to and entirely surrounding said heating spaces, said air flues communicating with the combustion chambers through said inlet passages.

7 In a muffle furnace construction, a muffle chamber, a series of independent combustion chambers disposed longitudinally over and extending laterally of the top of the chamber and having side and bottom flues in communication therewith, exit flues at the bottom of the construction respectively in communication with the different ends of the combustion chambers, a recuperator between the exit flues and the muffle chamber, laterally extending air flues for preheating air passing through the recuperator and in communication with side and top air vflues located adjacent to the side combustion flues and the combustion chambers respectively, and means disposed above said chambers for admitting fuel thereto.

8. In a muflle furnace construction, in combination with a muffle having a plurality of independent combustion chambers disposed adjacent to the top of the muffle and having centrally disposed inlet passages, means leading from each end of each of the combustion chambers to a central exit at a point below the muffle, lateral passages in communication with the exit, a centrally disposed chimney flue, a longitudinal series of flues disposed on each side of the chimney flue, means connecting the lateral passages with said series of flues, means for admitting a gaseous combustible supply to said combustion chambers through said inlets above the inufile, and means for preheating air and mixing it with the gaseous sup ply above the inuifle said latter means including a recuperator structure disposed below the muffie.

In testimony whereof I affix my signature in presence or two wltnesses.

WALTER O. AMSLER.

Witnesses S. A. MGFARLAND, WV. G. DOOLI'ITLE. 

